Organometallic compounds

ABSTRACT

The invention relates to organometallic compounds which are intramolecularly stabilized, and also to their use for the production of thin films and epitaxial layers by gas-phase deposition.

The invention relates to organometallic compounds which containaluminum, gallium or indium as metals, and also to the use of saidcompounds for the production of thin films or epitaxial layers bygas-phase deposition.

The deposition of such layers either from pure elements of the thirdgroup or from III-V combinations with other elements, such as forexample gallium arsenide, indium phosphide or gallium phosphide, can beused to produce electronic and opto-electronic circuit elements,compound semiconductors and lasers. The deposition of said layers takesplace from the gas phase.

The properties of these films depend on the deposition conditions andthe chemical composition of the film deposited.

All the known methods such as the Metal-Organic Chemical VaporDeposition (MOCVD) method, the Photo-Metal-Organic Vapor Phase(Photo-MOVP) method in which the substances are decomposed by UVirradiation, the Laser Chemical Vapor Deposition (Laser CVD) method orthe Metal-Organic Magnetron Scattering (MOMS) method, are suitable fordeposition from the gas phase. The advantages over other methods are acontrollable layer growth, a precise doping control and also simplehandling and production-friendliness owing to the normal-pressure orlow-pressure conditions.

In the MOCVD method, organometallic compounds are used which decomposeto deposit the metal at a temperature below 1100° C. Typical apparatuseswhich are currently used for MOCVD comprise a "bubbler" having a feedfor the organometallic component, a reaction chamber which contains thesubstrate to be coated, and also a source of a carrier gas, which shouldbe inert toward the organometallic component. The "bubbler" is kept at aconstant, relatively low temperature which is preferably above themelting point of the organometallic compound, but far below thedecomposition temperature. The reaction chamber or decomposition chamberis preferably at a very much higher temperature which is below 1100° C.,at which temperature the organometallic compound completely decomposesand the metal is deposited. The organometallic compound is converted tothe vapor state by the carrier gas and is passed through a lock into thedecomposition chamber with the carrier gas. The mass flow rate of thevapor can readily be controlled and a controlled growth of the thinlayers is consequently also possible.

Hitherto, metal alkyls such as, for example, trimethylgallium,trimethylaluminum or trimethylindium have mainly been used for gas-phasedeposition. These compounds are, however, extremely sensitive to air,spontaneously ignitable and partially decomposable even at roomtemperature. Elaborate safety measures are therefore necessary for theproduction, the transportation, the storage and the application of thesecompounds. A few, somewhat more stable adducts of the metal alkyls withLewis bases such as, for example, trimethylamine and triphenylphosphineare also known (described, for example, in GB 2,123,422, EP-A 108,469 orEP-A 176,537), but these are only suitable to a limited extent forgas-phase deposition owing to the low vapor pressure.

It was therefore the object of the present invention to find metal alkylcompounds which are simple to handle and are stable at room temperatureand which can be decomposed from the gas phase, that is to say aresuitable for the various methods of gas-phase deposition.

It has now been found that organometallic compounds of aluminum, galliumand indium which are intramolecularly stabilized are outstandinglysuitable for gas-phase deposition.

A few intramolecularly stabilized compounds of this type are described,for example, in German Offenlegungsschrift 3,631,469. This applicationdescribes, however, novel organometallic compounds having anintramolecular stabilization via a nitrogen, phosphorus, arsenic orantimony atom, or also having an intramolecular stabilization viafluorine atoms. All these intramolecularly stabilized compounds have ahigh stability toward air and oxygen, and they are therefore simple tohandle and are outstandingly suitable for gas-phase deposition.

The invention consequently relates to organometallic compounds of theformula I: ##STR1## wherein

M denotes aluminum, indium or gallium,

Y denotes --NR³ R⁴, --PR³ R⁴, --AsR³ R⁴, --SbR³ R⁴, --F or aperfluorinated alkyl group containing 1-7 carbon atoms,

X denotes, if Y=--F or a perfluorinated alkyl group containing 1-7carbon atoms:

--(CHR⁵)_(n) where n=1, 2, 3, 4 or 5,

o--(CH₂)_(p) --C₆ H₄ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₆ H₁₀ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₆ H₈ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₆ H₆ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₈ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₆ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₄ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₄ H₆ --(CH₂)_(q) --, or a single bond, or if Y=--NR³R⁴, --PR³ R⁴, --AsR⁴ R⁴ or --SbR³ R⁴ :

o--C₆ H₄ --,

1,2--C₆ H₁₀ --,

o--(CH₂)_(r) --C₆ H₄ --(CH₂)_(s) --,

1,2--(CH₂)_(r) --C₆ H₁₀ --(CH₂)_(s) --,

1,2--(CH₂)_(p) --C₆ H₈ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₆ H₆ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₈ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₆ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₄ --(CH₂)_(q) -- or

1,2--(CH₂)_(p) --C₄ H₆ --(CH₂)_(q) --,

r and s in each case denote, independently of each other, 1, 2 or 3,

p and q in each case denote, independently of each other, 0, 1, 2 or 3,

R¹, R², R³ and R⁴ in each case denote, independently of each other, analkyl group or alkenyl group containing up to 8 carbon atoms, it beingpossible for these groups to be partially or completely fluorinated, acycloalkyl group or cycloalkenyl group containing 3-8 carbon atoms or aphenyl group,

and

R⁵ in each case denotes H or an alkyl group containing 1-4 carbon atoms,which may also be partially or completely fluorinated.

The invention further relates to the use of the compounds of the formulaI for gas-phase deposition and also to a process for producing thinfilms or epitaxial layers by gas-phase deposition of the metal or of aIII-V combination from organometallic compounds in which the compoundsof the formula I are used as organometallic substances.

The compounds of the formula I are intramolecularly stabilized byelectron transfer from the nitrogen, phosphorus, arsenic, antimony orfluorine atom to the electron-deficient III B element. They thereforehave a high stability toward air and oxygen. They are no longerspontaneously ignitable and are consequently simple to handle. In thegas phase, however, the compounds according to the invention can easilybe decomposed to deposit the metal. Since the compounds of the formula Icontain stable and readily detachable departing groups, a lowerincorporation of carbon results, and this has considerable advantagesfor the quality of the final products.

In formula I, M denotes aluminum (Al), gallium (Ga) or indium (In),preferably Ga or In.

Y preferably denotes F or a perfluorinated alkyl group containing 1-7carbon atoms and accordingly preferably denotes trifluoromethyl,pentafluoroethyl, heptafluoropropyl or nonafluorobutyl,undecafluoropentyl, tridecafluorohexyl or pentadecafluoroheptyl.

Furthermore, Y preferably represents an --NR³ R⁴ group, and furthermorealso preferably a --PR³ R⁴ or --AsR³ R⁴ group.

Subformula Ia comprises the compounds which contain F or aperfluorinated alkyl group. Those compounds: ##STR2## wherein

M denotes Al, In or Ga,

Y denotes F, trifluoromethyl, pentafluoroethyl, heptafluoropropyl,nonafluorobutyl, undecafluoropentyl, tridecafluorohexyl orpentadecafluoroheptyl,

X denotes

--(CHR⁵) where n=1, 2, 3, 4, or 5,

o--(CH₂)_(p) --C₆ H₄ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₆ H₁₀ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₆ H₈ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₆ H₆ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₈ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₆ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₄ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₄ H₆ --(CH₂)_(q) --, or a single bond,

p and q in each case denote, independently of each other, 0, 1, 2 or 3,

R¹ and R² in each case denote, independently of each other, an alkylgroup or alkenyl group containing up to 8 carbon atoms, it beingpossible for these groups to be partially or completely fluorinated, acycloalkyl group or cycloalkenyl group containing 3-8 carbon atoms or aphenyl group,

and

R⁵ in each case denotes H or an alkyl group containing 1-4 carbon atomswhich may also be partially or completely fluorinated, are particularlypreferred.

Those compounds of the subformula Ib are further preferred which containas Y an --N³ R⁴, --PR³ R⁴, --AsR³ R⁴ or --SbR³ R⁴ group: ##STR3##wherein

M denotes Al, In or Ga,

Y denotes --NR³ R⁴, --PR³ R⁴, --AsR³ R⁴ or --SbR³ R⁴,

X denotes

o--C₆ H₄ --,

1,2--C₆ H₁₀ --,

o--(CH₂)_(r) --C₆ H₄ --(CH₂)_(s) --,

1,2--(CH₂)_(r) --C₆ H₁₀ --(CH₂)_(s) --,

1,2--(CH₂)_(p) --C₆ H₈ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₆ H₆ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₈ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₆ --(CH₂)_(q) --,

1,2--(CH₂)_(p) --C₅ H₄ --(CH₂)_(q) -- or

1,2--(CH₂)_(p) --C₄ H₆ --(CH₂)_(q) --,

r and s in each case denote, independently of each other, 1, 2 or 3,

p and q in each case denote, independently of each other, 0, 1, 2 or 3and

R¹, R², R³ and R⁴ in each case denote, independently of each other, analkyl group or alkenyl group containing up to 8 carbon atoms, it beingpossible for these groups to be partially or completely fluorinated, acycloalkyl group or cycloalkenyl group containing 3-8 carbon atoms or aphenyl group.

Among the compounds of the formula Ib, those are very particularlypreferred in which Y denotes --NR³ R⁴ or --PR³ R⁴.

In formula I and Ia, X denotes --(CHR⁵)_(n), where n =1, 2, 3, 4 or 5,and n is preferably =3 or 4. R⁵ represents either a hydrogen atom or analkyl group, which may also be partially or completely fluorinated,containing up to 4 carbon atoms and accordingly preferably denotesmethyl, ethyl, propyl, butyl, trifluoromethyl, tetrafluoroethyl,pentafluoroethyl or heptafluoropropyl. If R⁵ is an alkyl group orpartially or completely fluorinated alkyl group, preferably only in R⁵--(CHR⁵)_(n) -- is an alkyl group, the other R⁵ groups possibly presentthen denoting H.

In formula I and Ib, X preferably denotes o--C₆ H₄ --, 1,2--C₆ H₁₀ -- oralso o--(CH₂)_(r) --C₆ H₄ --(CH₂)₂ -- or 1,2--(CH₂)_(r) --C₆ H₁₀ --(CH₂)_(s) --, where r and s in each case denote, independently of eachother, 1, 2 or 3, preferably 1 or 2.

For X in formula Ia, the groups o--(CH₂)_(p) --C₆ H₄ -- (CH₂)_(q) -- and1,2--(CH₂)_(p) --C₆ H₁₀ --(CH₂)_(q), wherein p and q in each casedenote, independently of each other, 0, 1, 2 or 3, preferably 0, 1 or 2,are also especially preferred.

Very particularly preferred for X in the subformula Ia is the singlebond.

In the formulae I, Ia and Ib, X also further preferably denotes one ofthe following groupings (1)-(8) for --X--Y. ##STR4##

In the formulae (1), (2), (4) and (5), the double bonds may also besituated in all the other possible positions.

p and q in formula I preferably denote 1 or 2. In this connection, thosecompounds are preferred in which one of the groups p and q is 0 and theother denotes 1 or 2.

The radicals R¹, R², R³ and R⁴ in formula I may in each case denote astraight-chain or branched alkyl group containing 1-8 carbon atoms,preferably containing 1-4 carbon atoms. They are preferablystraight-chain and accordingly preferably denote methyl, ethyl, propyl,butyl, furthermore also pentyl, hexyl, heptyl, octyl, isopropyl,sec-butyl, tert-butyl, 2-methylpentyl, 3-methylpentyl or 2-octyl. Thealkyl radicals may be partially or even completely fluorinated anddenote, for example, monofluoromethyl, trifluoromethyl, difluoroethyl,trifluoroethyl, pentafluoroethyl or trifluoropropyl.

If R¹, R², R³ and/or R⁴ denote a cycloalkyl or cycloalkenyl groupcontaining 3-8 carbon atoms, they preferably denote cyclopropyl,cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl,cyclohexadienyl, cycloheptyl, cycloheptenyl, cycloheptadienyl,cyclooctyl, cyclooctenyl, cyclooctadienyl, cyclooctatrienyl orcyclooctatetraenyl.

Preferably, R¹, R², R³ and/or R⁴ also represent alkenyl groupscontaining 3-8 carbon atoms, preferably 3-5 carbon atoms. Theyaccordingly preferably denote propenyl, butenyl, pentenyl, andfurthermore hexenyl, heptenyl or octenyl.

Compounds of the formula I are furthermore preferred wherein R¹, R², R³and/or R⁴ denote a phenyl group. Said phenyl group may also be presentin substituted form. Since these substituents have no essentialinfluence on the intended application, all those substituents areallowed which do not have any disturbing influence on the decompositionreaction.

The compounds of the formula Ia wherein Y denotes a perfluorinated alkylgroup and R¹ and R² also denote alkyl groups which are partially or evencompletely fluorinated are also particularly preferred.

The following compounds of the formulae 7-27 represent a smaller groupof particularly preferred compounds of the formula I: ##STR5##

The compounds of the formulae I, Ia and Ib are outstandingly suitablefor the MOCVD epitaxy or MOCVD method since they decompose at elevatedtemperatures to release the corresponding metal. They are also suitablefor the other methods of gas-phase deposition such as photo-MOVP, laserCVD or MOMS.

The compounds of the formulae I, Ia and Ib are prepared by methods knownper se, such as are described in the literature (for example, G. Bahr,P. Burbar, Methoden der organischen Chemie [Methods of organicchemistry], volume XIII/4, Georg Thieme Verlag, Stuttgart (1970)) and,to be specific, under reaction conditions which are known and suitablefor the reactions mentioned. At the same time, use may also be made ofvariants which are known per se and are not mentioned here in anydetail.

Thus, compounds of the formulae I, Ia and Ib can be prepared, forexample, by reacting metal alkyl chlorides with an alkali-metal organylof the corresponding Lewis base or a Grignard compound in an inertsolvent.

The reactions are preferably carried out in inert solvents. In thisconnection, all those solvents which do not disturb the reaction and donot interfere with the course of the reaction are suitable as solvents.The reaction temperatures essentially correspond to those which areknown from the literature for the preparation of similar compounds.

In the process according to the invention for producing thin films orepitaxial layers on any desired substrates, the intramolecularlystabilized, organometallic compounds of the formula I are used asstarting compounds in the gas-phase deposition processes, known per se,of organometallic compounds.

In the process according to the invention, to produce compoundsemiconductors, and optical and optoelectronic components, one or morecompounds, which are gaseous under the reaction conditions used, ofarsenic, antimony or phosphorus, for example AsH₃, As(CH₃)₃, PH₃ or SbH₃are added during the deposition process in the decomposition chamber. Afurther variant of the process according to the invention is to adddopants additionally to the organometallic compounds of the formula Iaccording to the invention during the deposition process. In thisconnection, volatile organometallic compounds of iron, magnesium, zincor chromium are used as dopants. Preferred compounds in this connectionare considered to be, for example, Zn(CH₃)₂, Mg(CH₃)₂ or Fe(C₅ H₅)₂.

It is further possible to add the compounds of the formula I as dopantsduring the deposition process of other organometallic compounds.

The layers produced by the processes according to the invention can beused to produce electronic and optoelectronic circuit elements, compoundsemiconductors or lasers.

Since only approximately 1-10% of the free metal alkyls used can bedeposited as epitaxial layer on the substrate for thermodynamic reasonsin the epitaxial systems at present in use, the destruction of theexcess metal alkyls, which cannot be recovered owing to their extremesensitivity, represents a considerable problem. The compounds of theformula I according to the invention, on the other hand, open up newpossibilities for the safe destruction or for the recovery of thevaluable III B compounds owing to their high stability.

The following examples are intended to illustrate the invention in moredetail. Temperatures are always specified in degrees characterized inthat Celsius. Mp. denotes melting point and Bp. denotes boiling point

EXAMPLE 1

2.92 g (20 mmol) of trifluoromethylbenzene and 13.3 ml (1.5 N =20 mmol)of n-butyllithium (in hexane) are heated under reflux in an ether/hexanesolution (50 ml/25 ml) for approximately 8 hours. The mixture is thencooled to -40° and 1.62 g (12 mmol) of dimethylgallium chloride in 30 mlof hexane are added.

Precipitated lithium chloride is filtered off, the solvent is evaporatedoff and the residue is sublimed in vacuo.o-Trifluoromethylphenyldimethylgallium is obtained as a white solid, Mp.32°.

The following are prepared in an analogous manner:

o-Trifluoromethylphenyldiethylgallium

o-Trifluoromethylphenyldipropylgallium

o-Trifluoromethylphenyldibutylgallium

o-Trifluoromethylphenyldimethylaluminum

o-Trifluoromethylphenyldiethylaluminum

o-Trifluoromethylphenyldipropylaluminum

o-Trifluoromethylphenyldiisobutylaluminum

o-Trifluoromethylphenyldimethylindium

o-Trifluoromethylphenyldiethylindium

o-Trifluoromethylphenyldiisopropylindium

o-Trifluoromethylphenyldibutvlindium

3,3,3-Trifluoropropyldimethylgallium

3,3,3-Trifluoropropyldiethylgallium

3,3,3-Trifluoropropylmethylethylgallium

3,3,3-Trifluoropropyldipropylgallium

3,3,3-Trifluoropropyldi-sec-butylgallium

3,3,3-Trifluoropropyldipentylgallium

3,3,3-Trifluoropropyldimethylaluminum

3,3,3-Trifluoropropyldipropylaluminum

3,3,3-Trifluoropropyldiethylindium

3,3,3-Trifluoropropyldiisopropylindium

3-Monofluoropropyldimethylgallium

3-Monofluoropropyldimethylaluminum

3-Monofluoropropyldimethylindium

3-Monofluoropropyldiethylgallium

3-Monofluoroprop-vldiethylaluminum

3-Monofluoropropyldiethylindium

2-Monofluoroethyldimethylgallium

2-Monofluoroethyldiethylgallium

2-Monofluoroethyldipropylgallium

2-Monofluoroethyldimethylaluminum

2-Monofluoroethyldiethylaluminum

2-Monofluoroethyldi-tert-butylaluminum

2-Monofluoroethyldiethylindium

2-Monofluoroethyldipentylindium

EXAMPLE 2

13.81 g (69 mmol) of bromodimethylaniline in 100 ml of ether are addedto 1.23 g (177 mmol) of lithium in 60 ml of ether and stirring iscarried out for 12 hours at 20°. Then heating is carried out for 2 hoursto boiling point. After cooling, the solvent is removed in vacuo, hexaneis added and the LiCl is filtered off. On cooling to -30°, thecorresponding Li compound crystallizes out, and is isolated and dried.

4.6 g (34 mmol) of dimethylgallium chloride in 80 ml of pentane are thenadded at -40° to a suspension of 4.8 g (37.8 mmol) of this Li compoundin pentane. The mixture is then stirred for 12 hours at room temperatureand heated for a further 2 hours under reflux. The LiCl is filtered off,the solvent is distilled off in vacuo, and the residue has addedpentane/toluene (20/1) to it and is cooled to -30°. During this process,o-dimethylaminophenyldimethylgallium crystallizes out which, afterisolation, has a melting point of 104°.

The following are prepared in an analogous manner:

o-Dimethylaminophenyldiethylgallium

o-Dimethylaminophenyldipropylgallium

o-Dimethylaminophenyldibutylgallium

o-Dimethylaminophenyldimethylindium

o-Dimethylaminophenyldiethylindium

o-Dimethylaminophenyldiisopropylindium

o-Dimethylaminophenyldibutylindium

o-Dimethylaminophenyldimethylaluminum

o-Dimethylaminophenyldiethylaluminum

o-Dimethylaminophenyldipropylaluminum

o-Dimethylaminophenyldi-tert-butylaluminum

o-Dimethylaminophenyldipentylaluminum

o-Diethylaminophenyldimethylgallium

o-Diethylaminophenyldiethylaluminum

o-Diethylaminophenyldipropylindium

o-Dipropylaminophenyldimethylindium

o-Dipropylaminophenyldiethylgallium

o-Dipropylaminophenyldiisopropylaluminum

o-Dimethylaminomethylbenzyldimethylaluminum

o-Dimethylaminomethylbenz-vldiethylgallium

o-Dimethylaminomethylbenzyldipropylindium

1,2-Diethylaminomethylcyclohexylmethyldimethylgallium

1,2-Diethylaminomethylcyclohexylmethyldiethylgalliun

1,2-Diethylaminomethylcyclohexylmethyldiethylaluminum

1,2-Diethylaminomethylcyclohexylmethyldipropylaluminum

1,2-Diethylaminomethylcyclohexylmethyldibutylindium

1,2-Diethylaminomethylcyclohexylmethyldimethylindium

1,2-Dimethylaminomethylcyclopentyldimethylgallium

1,2-Dimethylaminomethylcyclopentyldiethylindium

1,2-Dimethylaminomethylcyclopentyldipropylaluminum

EXAMPLE 3

5.25 g (22 mmol) of o-trifluoromethylbenzyl bromide in 10 ml ofether/hexane are added at -50° to a mixture of 45 ml of ether/hexane(2:1) and 14.7 ml (1.5N =22 mmol) of n-butyllithium. After stirring for15 minutes, 2.1 g (16 mmol) of dimethylgallium chloride in 20 ml ofhexane are added. Then the reaction mixture is allowed to come to roomtemperature, it is stirred for 24 hours, and the LiCl is filtered offand the solvent removed. After sublimation in vacuo,o-trifluoromethylbenzyldimethylgallium is obtained with a Mp. 35°-38°.

The following are prepared in an analogous manner:

o-Trifluoromethylbenzyldiethylgallium

o-Trifluoromethylbenzyldipropylgallium

o-Trifluoromethylbenzyldibutylgallium

o-Trifluoromethylbenzyldimethylaluminum

o-Trifluoromethylbenzyldiethylaluminum

o-Trifluoromethylbenzyldipropylaluminum

o-Trifluoromethylbenzyldibutylaluminum

o-Trifluoromethylbenzyldipentylaluminum

o-Trifluoromethylbenzylethylpropylaluminum

o-Trifluoromethylbenzyldimethylindium

o-Trifluoromethylbenzyldiethylindium

o-Trifluoromethylbenzyldiisopropylindium

o-(2,2,2-Trifluoroethyl)benzyldimethylgallium

o-(2,2,2-Trifluoroethyl)benzyldiethylgallium

o-(2,2,2-Trifluoroethyl)benzyldiethylaluminum

o-(2,2,2-Trifluoroethyl)benzylmethylethylaluminum

o-(2,2,2-Trifluoroethyl)benzyldipropylindium

o-(2,2,2-Trifluoroethyl)benzyldimethylindium

o-(2-Monofluoroethyl)benzyldiethylgallium

o-(2-Monofluoroethyl)benzyldimethylindium

o-(2-Monofluoroethyl)benzyldipentylaluminum

o-(2-Monofluoroethyl)phenyldimethylgallium

o-(2-Monofluoroethyl)phenyldiisopropylaluminum

o-(2-Monofluoroethyl)phenyldiethylindium

o-(3-Monofluoropropyl)phenyldimethylgallium

o-(3-Monofluoropropyl)phenylmethylethylgallium

o-(3-Monofluoropropyl)phenyldiethylaluminum

o-(3-Monofluoropropyl)phenyldi-tert-butylaluminum

o-(3-Monofluoropropyl)phenyldipropylindium

o-(3-Monofluoropropyl)phenyldiethylindium

o-(3-Monofluoropropyl)benzyldimethylgallium

o-(3-Monofluoropropyl)benzyldimethylaluminum

o-(3-Monofluoropropyl)benzyldimethylindium

o-(3-Monofluoropropyl)benzyldiethylindium

o-(3-Monofluoropropyl)benzyldiethylaluminum

o-(3-Monofluoropropyl)benzyldipropylgallium

o-(3-Monofluoropropyl)benzyldiisopropylgallium

o-(3-Monofluoropropyl)benzyldibutylaluminum

EXAMPLE 4

1.95 g (8.48 mmol) of (CF₃)₂ Cd . DME (DME=dimethoxyethane) in 20 ml ofbenzene are added slowly at -70° C. to a mixture of 20 ml of benzene and1 g (5.66 mmol) of GaCl₃. After heating to room temperature,tris(trifluoromethyl)gallium is obtained by fractional distillation.

The following are prepared in an analogous manner:

tris(trifluoromethyl)indium

tris(pentafluoroethyl)gallium

tris(pentafluoroethyl)indium

tris(heptafluoropropyl)gallium

tris(heptafluoropropyl)indium

We claim:
 1. Organometallic compounds of the formula I: ##STR6## wherein M denotes aluminum, indium or gallium,Y denotes --NR³ R⁴, --PR³ R⁴, --AsR³ R⁴, --SbR³ R⁴, --F or a perfluorinated alkyl group containing 1-7 carbon atoms, X denotes, if Y=--F or a perfluorinated alkyl group containing 1-7 carbon atoms:--(CHR⁵)_(n) where n=1, 2, 3, 4 or 5, o--(CH₂)_(p) --C₆ H₄ --(CH₂)_(q) --,
 1. 2--(CH₂)_(p) --C₆ H₁₀ --(CH₂)_(q) --,1,2--(CH₂)_(p) --C₆ H₈ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₆ H₆ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₅ H₈ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₅ H₆ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₅ H₄ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₄ H₆ --(CH₂)_(q) --, or if Y=--NR³ R⁴, --PR³ R⁴, --AsR³ R⁴ or --SbR³ R⁴ : o--C₆ H₄ --, 1,2--C₆ H₁₀ --, o--(CH₂)_(r) --C₆ H₄ --(CH₂)_(s) --, 1,2--(CH₂)_(r) --C₆ H₁₀ --(CH₂)_(s) --, 1,2--(CH₂)_(p) --C₆ H₈ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₆ H₆ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₅ H₈ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₅ H₆ --(CH₂)_(q) --, 1,2--(CH₂)_(p) --C₅ H₄ --(CH₂)_(q) -- or 1,2--(CH₂)_(p) --C₄ H₆ --(CH₂)_(q) --, r and s in each case denote, independently of each other, 1, 2 or 3, p and q in each case denote, independently of each other, 0, 1, 2 or 3, R¹, R², R³ and R⁴ in each case denote, independently of each other, an alkyl group or alkenyl group containing up to 8 carbon atoms, it being possible for these groups to be partially or completely fluorinated, a cycloalkyl group or cycloalkenyl group containing 3-8 carbon atoms or a phenyl group, and R⁵ in each case denotes H or an alkyl group containing 1-4 carbon atoms, which may also be partially or completely fluorinated.
 2. The use of the organometallic compounds of the formula I according to claim 1 for the gas-phase deposition of the metal of the main group III or of a III-V combination on substrates.
 3. The use of the organometallic compounds of the formula I according to claim 1 for the deposition of epitaxial layers.
 4. Process for the production of thin films on substrates by gas-phase deposition of the metal of the main group III or of a III-V combination from organometallic compounds, characterized in that the compounds of the formula I according to claim 1 are used as organometallic compounds.
 5. Process according to claim 4, characterized in that one or more compounds of arsenic, antimony or phosphorus which are gaseous under the reaction conditions used are supplied for the production of compound semiconductors, and of optical and opto-electronic components during the deposition process.
 6. Process according to claim 4, characterized in that dopants are added additionally to the organometallic compounds of the formula I during the deposition process.
 7. Process according to claim 4, characterized in that the compounds of the formula I are added as dopants during the deposition process of other organometallic compounds. 